Need help How to insert in while loop if the users put wrong number different from array given

Question

Hello everyone back again on my codings ....
I need helps on while loop infinite loop here I attached my code.
I need to show if the user put different numbers or other letters show messages that "invalide number"
https://code.sololearn.com/chGNKj5X5VId/?ref=app

Answer 1

Line 22:
if(barcode==price);{
);{ ?

Answer 2

Line 22
is if barcode is equal to the price
If show the total price